Trimming mechanism for sewing-machines.



APPLICATION HLED MAR-211 NH.

Patented Dec. 31, 1918.

TED STATES PATENT @FTTQE.

ALBERT H. DE VOE, 0F WESTFIELD, NEW JERSEY, ASSIGNOR TO THE SINGER MANU- FACTURING COMPANY, A CORPORATION OF NEW JERSEY.

TRIMMING MECHANISM FOR SEWING-MACHINES.

Specification of Letters Patent.

Patented Dec. 31, 1918.

Application filed March 27, 1917. Serial No. 157,609.

To all whom 62? may concern.-

Be it known that I, ALBERT H. De Von, a citizen of the United States, residing at Westfield, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Trimming Mech anisms for Sewing-Machines, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to trimming mechanisms for sewing machines.

It has for its object the improvement of the efficiency of trimming mechanisms so that they will stand up longer in service without resharpening of the blades. A further aim has been to simplify and compact the arrangement of a sewing machine equipped with a trimming mechanism.

The trimming mechanism comprises a ledger-blade adjustably mounted below the throat-plate and a movable blade sustained by a. flexible carrier which is supported and actuated through a pivotal connection with a rock-lever fulcrumed on the head of an overhanging arm on which is pivotally mounted a needle-operating lever that is operatively connected to the needle-bar and the rock-lever. The operative connections mentioned include a link having a perforated arm constituting a take-up for the thread passing to the needle. A second link hinged at a point in rear of and slightly below the overhanging arm is pivotally connected to the flexible blade-carrier and compels the movable blade thereon to reciprocate in a substantially perpendicular direction as it is actuated by the rock-lever.

Theinvention further consists in certain details of construction which will appear in the description of the invention embodied in the drawings, in which Figure 1 is a perspective view of the invention. Fig. 2 is a vertical section through the pivotal supporting and actuating connection of the blade-carrier. Fig. 3 is a horizontal section through the vertical limb of the bladecarrier.

T he invention is applicable to almost any type of stitch-forming mechanism. As shown it is embodied in a chain-stitch machine similar to that found in my pending application Serial No. 114,503, filed August 12, 1916. A needle 1 is reciprocated through a hole 2 in the throat-plate 3 by a needlelever i pivoted at 5 in the overhanging arm 6 and connected by a link 8 to a clamp 9 suitably fixed to the needle-bar 10. The clamp 9 has a vertical lug 11 tapped to receive a stud-screw 12 by which it is pivotally connected to the lower end of a link 13 having a lateral arm 14 pierced to receive thread passing to the needle and forming a take-up for controlling the thread in a manner 'well known. The link 13 is connected at its upper end to a stud-screw 12 tapped into one end of a rock-lever 15, the other end of which is fixed to a pin 16 pivotally supportd in a bearing bracket 17 secured to theoverhanging arm 6 in any suitable manner. by the set-screw 1.9 constrains the rock-lever to move in a plane parallel with a vertical plane through the line of stitch-formation.

A pair of cutting blades are located in advance and to one side of the needle. The lower or ledger-blade 20 is adjustably mounted beneath the throat-plate as shown and described in Patent to Grieb, No. 933,033, of August 31, 1909, a screw 21 affording means for adjusting it laterally. A second and movable blade 22, having a cutting edge 23 inclined to thehorizontal surface of the throat-plate, is removably and adjustably secured by a set-screw 24c in a suitably channeled lower end of a flexible blade-carrier 25 which is split as indicated at 25 to allow a firm grip on the blade. The blade-carrier has a vertical body-portion which is arranged substantially in parallelism with the needle-bar and atits upper end is bent at substantially right angles to its body-portion as clearly shown in the drawings. In the end of the bent portion of the blade-carrier a split boss 25 is formed and by means of the screw 26 it may be clamped on a sleeve 27 drilled to receive the pivot-pin 28 having a head 28, a shoulder 29, and a threaded extremity 30 screwed into the rock-lever 15 and clamped by a lock-nut 31. There is thus formed a pivotal supporting and actuating connection between the rock-lever 15 and the blade-carrier located in rear of the line in which the needle reciprocates. Intermediate its ends the blade-carrier has a laterally extending pin 32 slidably embraced by the boss 33 on the end of a link or hinge 34 fastened by the screw 35 to the rod 36 which is slidably supported in the bearing bosses 37 and 38 i A collar 18 fastened to the pin 16 sustained in rear of and slightly below the ve n n rm of e a ine 39- adjustablv secured on the rod 36 by the set-screw 40 is adapted to receive the thrust of a compressed spring 41 coiled about the rod as it reacts against the fixed bearing boss 38.

The presser-foot 42 is of any suitable form and as shown is equippedwith a hardened wear-plate 43 secured by screw 44, a slot 45 permitting adjustment so that it may be set against the movable blade. The throat-plate is also of old and well-known form and has serrations 46' on its upper face for-resisting rearward slip of the material' being operated upon; as itpasses through the machine. A chute for the trimmed olf- -material'is shown at lJ;

Features or principles underlying the invention, as it is at present understood, will now be mentioned:

Owingto the construction and arrangementofthe members 25, '34, 36 and- 41 thereis a tendency 'tolspring or buckle-the flexible member 25 so as to incline the blade 22 relative tothe lineof feed; the portion of; the blade nearest theoperat-ors position extending toward the left. Inthis way thetr-imming mechanismhas an action similar to that of a pair ofscissors the blades contacting at substantially thetrimmingrpoint only; Thus a veryeflicient'action of thecut ting mechanism is secured and the blades have a self-sharpeningaction which enables them to stand up inserviceifor a considerable-time withoutregrind-ing.

Slight lateral adjustment of the ledgerblade-in either direction maybe made with-e out. the necessity of separately adj ustingthe movable blade because of the flexible character of the carrier together with the; application of a constant spring pressure asabovementioned; To lavoiditoo great or too small an angular relation between. the. cutting edges of the blades.- and-a consequenttloss-of efficiency and durability. thefcarr'ier may be separately: adju'stedlaterally by. means of; the split boss and screw formed-jo-n lts-upper.

operation by a flange or rib 48 ,Fig. 3; formed integrally I (or in, any, suitable manner) onthe front edge of the. vertical. leg of; the

blade-carrier,

By the fiatwise. V arrangement of the -blad carrier, rock-lever and :the link;actnating,the

rockslever and alsoloy mounting thetake-up directly on the linkactuat-ing-the rock-lever themechanism is simplified and; compacted Having thus set forththe natu r e he in: vention, what-Iv claim herein 1s n ewins m chi e; n' m inat ony an edlea rymei ar, a e dlea pes tlna A collar lever and a link connecting said bar and operating lever, a ledger-blade, a movable blade cooperating therewith, a pivoted carrier for said movable blade, a take-up for controllingthe needle-thread, common means actuated by said needle-bar operating lever for operating said take-up and bladefcarrier.

2. In a sewing machine having a needle and a needlebar, a needle-bar operating lever, a link connecting said bar and said operating lever, a lower blade, an upper movable blade cooperating therewith, a carrier for said movable blade, a rock-lever having a fixed fulcrum, a link connecting said rock-lever and needle-bar, a take-up operated' by said last-named link for controlling the thread carried bythe needle, a pivotal connection between said rock-lever and said blade-carrier, and means for guiding the movable blade.

3; In a sewing machine, in combination, a needle, a needle-bar, a; needle-operating lever, a link connectingsaid bar andoperating lever. a ledger-b-lade-,a movable blade co operating therewith, a carrier for said movable blade, a rock-lever fulcrumed at one end, a link connected to the other endof said rock-lever, a'connectionbetween said link and said needle-bar, a pivotal connection'between saidblade-carrier and saidrockdever intermedia'tethe ends ofthe rock-lever, a thread-controlling device actuated by said link, and means for guiding the movable blade in a substantially straight'line.

' In a sewing machine, in'combination, a needle, a needle-bar, a needle-operating lever, a link connecting Said'bar and operat-- inglever, a ledger-blade, a movableblade cooperating, therewith, a carrier for said movable blade, means operatively supporting said blade-carrier, a takeup controlling thethread carried by theneedle, and com monmeans for actuating aid takeeup and ad ar ie e Ina trimmer for sewing machines, a ledger-blade, a movable blade cooperating therewith, a needle carrying bar, a ca rrier, pivoted intermediate its ends and holding at itsv lower end. said movable blade, and means for sustaining and vactuating said carrier from its upper end, saidmeans'includinga rock-lever movable in a planeparr allel to the plane-of-the movable blade, a link, connecting said rock-lever and needle bar, said carrier of the, movable blade being pivoted to saidrock-leyer intermediatedts connection with the link and its. fulcrum,

6. In a trimmer for sewing machines having. a, needle-carrying bar and actuating mechanism therefor, in combinati0n with a, ledger-blade, a movableblade in advance of said needlebar, a: carrier; for saidmovable blade, and means for supporting and actu ating said carrier including, a link pivoted arear f a need e eppp ingg n ra a tuating rock-lever pivoted to the upper end of said carrier, a link connecting said rocklever and needle-bar, said needle-bar having a longer stroke than said movable blade mounted on said carrier.

7 In a trimmer for sewing machines having a needle, suitable actuating mechanism therefor and a throat-plate, in combination, a ledger-blade having a cutting edge substantially flush with the throat-plate, a mov able blade cooperating therewith and having a cutting edge inclined to the throat plate, a flexible carrier for said movable blade arranged in a plane substantially parallel to avertical plane through the line of stitch-formation, means connected to said blade-carrier intermediate its ends and in advance of the line of needle actuation for guiding the movable blade in a substantially perpendicular line, means connected to the upper portion of the blade-carrier in rear of the line of needle-actuation for supporting and actuating the carrier, and a spring pressing on the carrier at a point in advance of the line of needle actuation in a direction tending to flex the carrier toward the ledgerblade whereby the cutting edge of the movable blade may be moved downwardly at an angle across the cutting edge of the ledger-blade.

8. In a trimmer for sewing machines hav ing a needle, suitable actuating mechanism therefor, and a throat-plate, in combination, an adjustable ledger-blade having a cutting edge substantially flush with the throat plate, a movable blade cooperating therewith and having a cutting edge inclined to the horizontal, a flexible carrier for said movable blade arranged in a plane substan- Copies of this patent may be tially parallel to a vertical plane through the line of titch-formation, means connected to said blade-carrier intermediate its ends and in advance of the line of needleactuation for guiding the movable blade in a substantially perpendicular line, means adjustably connected to the upper portion of the blade-carrier in rear of the line of needle-actuation for supporting and actuating the carrier, and a spring for pressing the means for guiding the carrier in a direction tending to flex the carrier toward the ledger-blade whereby the cutting edge of the movable blade may be operatively main tained at a small angle to the cutting edge of the ledger-blade.

9. In a trimmer for sewing machines having a needle and suitable actuating mechanism therefor, a ledger-blade, a movable blade cooperating therewith, and a flexible carrier for said movable blade having a substantially vertical portion arranged in parallelism with and in advance of the needle, said flexible carrier also having an upper end portion arranged rearwardlyof the vertical portion, means actuating and supporting said carrier and pivotally connected to the upper end portion thereof, means com pelling the carrier to move in a substantially perpendicular direction, and means constantly pressing said flexible carrier sidewise at a point remote from its pivotal actuating and supporting connection whereby the cutting edge of the movable blade may be made to assume a slight angular relation to the ledger-blade.

In testimony whereof, I have signed my name to this specification.

ALBERT H. DE VOE.

obtained for five cents each, by addressing the "Commissioner of Patents,

Washington, D. 0. 

